A number of locking mechanisms have been devised to prevent the unauthorized use of trigger-activated equipment. These concerns arise relating to use of such equipment by unauthorized persons, including children and persons who tamper with such equipment. With regard to firearms, danger may arise when persons with illicit purposes take without right weapons from police officers or private persons. While some equipment, particularly firearms, typically have a safety device, such devices are deficient as impediments to prevent such unauthorized uses. Locks have been created which attach to the trigger of equipment to prevent access to the trigger, and thus render the equipment inoperable. Representative patents dealing with firearm triggers include BROOKS, U.S. Pat. No. 5,090,148; BAKO, U.S. Pat. No. 4,499,681; and CERVANTES, U.S. Pat. No. 4,084,341. Such locks are cumbersome and difficult to remove or to readily operate so as to permit use by authorized users. This problem can reduce the effectiveness in emergency situations. For example, the police officer in immediate need of a firearm, or the private citizen who must use a firearm for self-defense, could suffer if significant delays were involved in making the firearm operational. While the firearm safety device in BROOKS attempted to alleviate such cumbersomeness by integrating the lock into the firearm system, the disclosed lock involves a complicated multi-wheel system which requires being able to visually see the dials utilized upon the firearm safety mechanism in order to make the weapon operational. Such safety mechanisms also involve numerous mechanical elements, the complexity of which leads to maintenance or operational problems. It would be desirous to provide a safety mechanism which can lock equipment, prevent unauthorized use of equipment, such as a firearm or tool, yet be readily activated by an authorized user. It would also be desirable if the locking mechanism would require no external accessories, such that the authorized user could readily activate, or deactivate, the device at any time. It would also be desirable to provide a safety lock which can be activated or deactivated without viewing the lock. It would also be desirable to provide a safety lock which is not bulky, and which would not hamper operation of the equipment when installed.